Construction and control of planetary mills



Oct. 12, 1965 1-. SENDZIMIR CONSTRUCTION AND CONTROL OF PLANETARY MILLS 5 Sheets-Sheet 1 Original Filed July 29, 1959 INVENTOR. 720511.92 SiA/PZ/M/ ATTORNEYS Oct. 12, 1965 1-. SENDZIMIR 3,210,981

CONSTRUCTION AND CONTROL OF PLANETARY MILLS Original Filed July 29, 1959 5 Sheets-Sheet 2 INVENTOR. 72050.52 DZ/M/@,

Sf/zmm 496? ATTORNEYS Oct. 12, 196 5 -,s N z1 R 3,210,981

CONSTRUCTION AND CONTROL OF PLANETARY MILLS Original Filed July 29, 1959 5 Sheets-Sheet 3 ll 7' //Z7 INVENTOR.

72051152 Sf/VDZ/M/Q,

FIG. 3 g1W,-mdu1w BY QQ ILM i? $6 0M:

ATTORNEYS,

Oct. 12, 1965 1-. SENDZIMIR CONSTRUCTION AND CONTROL OF PLANETARY MILLS Original Filed July 29, 1959 5 Sheets-Sheet 4 INVENTOR. fiwiusz fii/vozr/w/ BY 5 lea/die, am 4 ham ATTORNEYS Oct. 12, 1965 -r. SENDZlMlR 3,210,981

CONSTRUCTION AND CONTROL OF PLANETARY MILLS Original Filed July 29, 1959 5 Sheets-Sheet 5 INVENTOR. 72054492 5/v0z/M//e,

BY 16mm I hzuw 2 ATTORNEYS United States Patent 3,210,981 CONSTRUCTION AND CONTROL OF PLANETARY MILLS Tadeusz Sendzirnir, Sendzimir, Ina, Waterbury, Conn. Original application July 29, 1959, Ser. No. 830,216, now

Patent No. 3,133,979, dated June 30, 1964. Divided and this application June 29, 1964, Ser. No. 378,748

8 Claims. (Cl. 72187) This application is a division of my copending application Serial No. 830,216, filed July 29, 1959 and bearing the same title, now United States Letters Patent No. 3,138,979 issued June 30, 1964.

This invention relates to planetary rolling mills such as are described in United States Patents 2,710,550 and 2,811,060 and in the copending United States application Series No. 436,075 of applicant, filed June 11, 1954 and entitled Dual Drive Planetary Reducing Mills, now United States Letters Patent No. 2,932,997, issued April 19, 1960, and also to mills such as those described in British Patent 609,706 to E. M. Picken, i.e. to mills of the type in which successive pairs of working rolls, one on each side, pass progressively across a zone of plastic deformation of a work piece while in rolling contact therewith. The working rolls are arranged in planetary assemblies about each of a pair of backing rolls or their equivalent. The direction of translation of the working rolls while in contact with the work piece is usually from the unreduced portion toward the reduced portion of the work piece; and while each pair of working rolls may make a reduction in the zone of deformation comparable to that produced in a single pass in a conventional mill where the working rolls rotate around a fixed axis, and where reductions of between and 35% in a hot rolling operation are exemplary, in the planetary mills of the type here under discussion, by reason of the fact that there are many pairs of working rolls which pass in a rapid succession post each portion of the work piece in the zone of deformation, the total reduction is usually many times more than that on any conventional mill. A planetary mill acting to reduce a steel slab 40 in. wide and 3 /2 in. thick to strip metal having a 40 in. width and a thickness of about 0.010 in. is exemplary but not limiting. The reduction just set forth is a 97% reduction and produces an extension of the metal to 35 times its original length.

The teachings of this application are directed primarily to the correction of difliculties which have been found to arise during the actual operation of the mill on a work piece or series of work pieces. It has been found that during the rolling of slabs certain operational characteristics tend to arise which interfere with the proper reduction of the work piece, and with the operation of the mill as a mechanical unit and which in some instances result in serious mechanical damage to the mill, including broken gear teeth, twisted shafts, damaged keyways and the like. These difficulties have now been traced to inequalities in the operation of the working rolls, which inequalities are conveniently indicated by the term synchronization using that term in a generic sense. Means have hitherto been provided in mills of the type to which this invention is addressed for causing the opposite ones of the working rolls to contact the work piece simultaneously, which is an aspect of synchronization; but it has been found that if something occurs to disturb the proper coaction of the rolls during a rolling operation, the apparatus heretofore provided for causing opposite Working rolls to contact the work piece simultaneously and which generally comprises gears, shafts, couplings and power units is subject to shock load which is sometimes unpredictably high. It has been found further that once a planetary mill develops a condition in which the working rolls depart from proper coaction further operation of the mill usually increases the degree of asynchronization. The greater the departure of the working rolls in the zone of plastic deformation from proper coaction, the greater will be the force needed to prevent further departure from proper coaction. It has not been found possible to cure these defects by making the hitherto known synchronizing means extremely heavy and rigid.

There are forces in the planetary mill which tend to interfere with proper coaction of the working rolls in the zone of plastic deformation despite extreme rigidity in the means hitherto provided for synchronization. These forces arise during rolling for various reasons including, among others, changes occurring as a result of wear, local expansion due to heat, inequalities in the fiow of lubricant, and inequalities in the work piece. Work pieces may not only vary in physical shape in different parts, but they also may vary in temperature sporadically, and from side to side. There is almost always a temperature variation in the direction of the length of the work piece, the trailing end of a work piece being commonly at a lower temperature than the leading end of the same, or a successive work piece. For example, a mill with newly reground rolls and checked for synchronism may operate perfectly for half a day and then gradually develop a tendency such that the first end of each strip points sharply downwards (or upwards) instead of horizontally, even to the point of getting under the stripper and causing a loop, and in consequence, a cobble. This is usually accompanied by a shifting of the slab vertically, in the zone of deformation, away from the roll assembly that is in advance.

This condition in turn causes the angle of incidence of the lower working rolls against the slab to become greater which may lead to development of backfins (such as described in U.S. Patent 2,710,550 above cited). In their incipient stage, such backfins are small discon tinuous rolled-in-slivers and are very detrimental to the surface quality of the finished strip.

When continuing operation under these conditions the operator must be on the alert because the situation may eaggravate itself in a matter of a few seconds, and unless the mill is not suddenly stopped, serious damage is caused.

The term synchronization as used herein is intended to be inclusive of the matter of parallel alignment of the axes of the working rolls with the axes of the backing rolls. If this alignment is departed from, the working rolls come out of parallelism and are skewed. The consequence is usually a lateral translation of the slab in the working zone; and this occurs sometimes with such great force that no lateral guide is capable of holding it.

Defects in synchronization are also likely to occur due to the action of screwdown means when adjustments are made to change the final gauge of the material being rolled; and this brings up another difiiculty which could be termed a departure from symmetry, but for purposes of this application will be considered under the heading of synchonization because it affects synchronization. Where the upper backing roll is shifted vertically, as by means of conventional screwdowns, in order to change or adjust the gauge, the result is a shifting of the zone of plastic deformation above or below the plane of symmetry of the mill. Rolling is most eflicient when the plane of symmetry of the zone of plastic deformation lies midway between the paths of operation of the two sets of planetary working rolls. A shifting of the plane of symmetry toward or away from either planetary assembly produces in itself the effect of lack of synchronization of the working rolls.

While an experienced planetary mill operator is frequently able to note changes in the behavior of the mill in time to stop it before serious damage is done, in the past there has been no way of correcting any of the dimculties hereinabove mentioned excepting by resetting the mill elements which causes an interruption during which the mill cools down and the thermal equilibrium that affects synchronization is again upset.

Applicant has found that by carefully observing the position of the slab both in the vertical and lateral directions at the entry into the zone of deformation, and any tendency on the part of the slab to change its position, he could successfully anticipate the stepping of the rolls out of synchronism and cause the slab to return to its position in symmetry with the mill by adjusting the synchronizing elements in a direction opposite to the direction of such shifting. The development of this new method of operating the planetary mill has permitted rolling without interruption and has practically eliminated the danger of mechanical wrecks. It is, therefore, an object of this invention to provide means for such adjustment. The means herein taught may be controlled by an operator who is sensitive to any malfunction of the mill; but they also may be controlled by automatic mechanism.

It is thus an object of the invention to provide means whereby the simultaneous contacting of the work piece by opposite members of a pair of working rolls can be maintained by making appropriate adjustments during a rolling operation.

It is an object of the invention to provide a means whereby any skewing of the rolls may be controlled or corrected during a rolling operation.

It is an object of the invention to provide a means whereby the plane of symmetry of the zone of plastic deformation can be adjusted with. respect to the plane of symmetry of the mill during a rolling operation.

In speaking of these corrections and adjustments, it should be kept in mind that there are circumstances in which a controlled degree of asynchronization, a controlled degree of skewing, or a controlled departure of the plane of symmetry of the work piece from the plane of symmetry of the mill may be desirable to overcome certain specific conditions, usually conditions of inequality in the work piece itself; and that the term control as herein used is intended to be broad enough to cover the attainment of predetermined degrees of any of the aspects of asynchronization for specific purposes.

The attainment of the principal objects of the invention provides a number of ancillary advantages which also constitute objects of the invention, these, which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications, are accomplished by that construction and arrangement of parts and in that procedure of which certain exemplary embodiments will now be described. Reference is made to the accompanying drawings wherein:

FIG. 1 is a diagrammatic vertical cross section of a planetary mill including a pair of feed rolls, a pair of planetary assemblies, and a pair of planishing rolls, all included in the same housing. In this figure there is also illustrated a means for keeping a plurality of the working rolls of each planetary assembly in contact with the backing rolls on the sides opposite the zone of plastic deformation.

FIG. 2 is a longitudinal vertical section taken across the pair of planetary assemblies as shown in FIG. 1.

FIG. 3 is a partial vertical section showing a means for pre-loading the backing roll bearings.

FIG. 4 is a longitudinal vertical section taken through the plane of the finishing or planishing rolls of FIG. 1.

FIG. 5 is a diagrammatic longitudinal section through the pinions of an adjustable pinion stand coupled by spindles to a planetary mill such as those shown in FIG. 1.

FIG. 6 is a partial vertical sectional view of a planetary assembly as shown in FIGS. 1 and 4 showing the mounting of working rolls in their cages and their skewing adjustment and also showing a backing roll chock or bearing having screwdown features hereinafter described.

The various mechanical arrangements and construe tions hereinafter described have both a combined and an individual utility; that is to say, they not only interact and coact to a given end, namely the control of all of the factors of asynchronization as described above, providing a mill which is efiicient in its operation and essentially not subject to destructive mechanical shocks, but they are also individually useful as such and useful in combinations containing less than the total number of elements herein described. The order in which the various novel mechanical elements going to make up this invention are described herein is not to be taken as the order of their practical utility or importance. The endeavor has been to describe a mill or mills in a clear and understandable fashion from the standpoint of the functioning of all of the parts thereof.

Referring firs-t to FIG. 1, there is shown a planetary mill comprising a housing, part of which is shown at 1, a pair of backing rolls 112 and 113 mounted in the housing, assemblies 4 and 5 of planetary working rolls each surround-ing one of the backing rolls, and a slab 6 which is being reduced to a strip 7 in the zone of plastic deformation of the mill. It is usual in the operation of planetary mills of this type to roll the slab 6 in heated condition, but this constitutes no necessary limitation of the invention since the mill may be operated as a cold mill if desired.

FIG. 1 illustrates the provision of chocks or bearing elements for both of the backing rolls 112 and 113, which chocks also constitute adjustable screwdown means. The chocks are arcuate in peripheral contour and are mounted in circular recesses or perforations in the housing 1, while the necks of the backing rolls 112 and 113 are ecentrically mounted in the chocks. The chocks are indicated in the figure at 12 and 13 and means provided for rotating the chocks in the housing which will have the effect of moving the axes of the rolls 112 and 113 simultaneously toward and away from each other. While eccentric chocks are known, applicants chocks are limited in their periphery to an arc of a circle which permits a rotation over about 60 only. At the same time their eccentricity is many times larger than on known eccentric chocks permitting a full revolution.

While there are many ways in which the chocks may be rotated, a simple arrangement is shown in FIG. 1 in which the piston rod 14 of a fluid pressure cylinder 15 mounted on the upper end of the housing 1 is connected to the chocks 12 in an eccentric position. Similarly, the piston rod 16 of a fluid :pressure cylinder 17 mounted on the lower end of the housing 1 is connected to the chock 13 in an eccentric position. It will be evident that excitation of the fluid pressure cylinders will produce a limited rotative movement of the chocks 12 and 13, moving axes of the backing rolls 112 and 113 simultaneously toward and away from each other. If the two cylinders are actuated simultaneously, and equally, in the same operative direction the screwdown will be varied without changing the plane of symmetry of the mill. If the two cylinders are actuated simultaneously equally but in opposite operative directions, the screwdown of the mill will remain substantially the same but the plane of symemtry will be shifted. If the two cylinders are actuated differentially, the screwdown can be changed and the plane of symmetry simultaneously shifted.

During a rolling operation, the provision of a screwdown on both the backing rolls permits the operator (or automatic devices if desired) to make minute adjustments quickly and precisely in the position of the plane of symmetry of the mill. The arrangement also has a number of other advantages. It is only necessary to move each screwdown a little more than half the thickness of the slab to open the mill completely and release the slab as in the case of a cobble. Another advantage lies in the fact'that the arrangement permits aconsiderable, reduction in the :size of the mill housingJ-Inplanetary* mills as hitherto constructed, theupper backihgjoll had its ends or necks mounted in rectangularl'chocks or v It will be understood by '6. the skilled worker in the art that the various chocks heretofore'describedas rotatably m0unted.in the mill housing may be rotated by various not only had to be quite large in themselves, butthe provision of the slots (which had to'be substantially longer than the entire.range of movement of the.

screwdown, and the provision of screw.mcans 'thread ed into the upper part of the housing, considerably weakened the housing itself. Hence it was found necessary to use housings which were quite large as compared with the working parts of the mill. But in astructure such as that shown in'FIG. 1, since the roll-separating force is transmitted by the chock to the housing on a large curved area, the housing is subjected, in much the same way as a loadedpressure vessel, to tensional stresses primarily and to practically no bending moments. This very greatly reduces the deflection of the housing under load; and it has been found that housings designed as in FIG. I can weigh less than half of the necessary weight of former housing while possessing a rigidity 2 or-3 times greater. It becomes possible, moreover, even on fairly large sized mills such as those rolling strips'50 in. or more in width, to produce a complete mill housing including both end housing members and connecting beams such as those shown at 18, 19, 20 and 21 in FIG. 1 as a single casting. This adds substantially to the over-all rigidity and lateral stability of the mill. In a conventional type of mill of the same size, each end housing member would by itself weigh over 300,000 lbs. which make any combination of the two in a single casting impracticable.

It will be understood that in many mills guides will be provided to conduct the slab to a point as close as possible to the zone of engagement of the working-rolls with the work piece. These guides have not been illustrated in the drawings. It will be understood that where guides are used it will be within the scope of this invention to provide for adjustments of their positions transvcrsely of the zone of plastic deformation.

In some mills feeding is accomplished by feed rolls, and it is advantageous to locate such rolls as close as tudinalvertical sections of mills.

mechanical hydraulicor electricallydriven means. Ad-

justment of any'of these meansmay be whollyunder the bearings slidable in slots in the housing. These bearings control of the mill operator; but adjustment may also be effected by automatically acting means.

-Rcferenceis made to FIGS. 2 and 3 which are longi- In FIGJZ the end mill housing element 1 is shown ascontaining the rotary chocks 12 and 13. The opposite end-mill housing ele- 7 meat is indicated at In and is shown as containing the chocks 12a and 13a; The end housing elements 1 and 10 are interconnected by the beams 18 and 19. 3 Similarly the end mill housings 1 and 1a in FIG; 5 are shown as carrying the chocks 42. 43 and 42a, 43a, respectively for the planishing rolls 40 and 41.. Fluid pressure means for the several chocks are shown inFIG. 4 at 15, 11 and 15a, 17a and in FIG. Sat 44, 45 and'j44a, 45a. The chocks may be held axially in place 'inithe'respective housing elements by means of rings 56 or in other suitable ways. FIGS..4 and 5 illustrate not only'rwhat is meant by one piece housing as hereinabove set forth, but they also make it clear that since separate controllingmeans for the several chocks are provided on each side of the mill the scrcwdown effect may be adjusted transversely of the direction of rolling of the work piece. Thus if there is a discrepancy between the screwdown on one side and the screwdown on the other, this may be corrected; and it is also possible deliberately to adjust the screwdown on the one side of the mill so that the rolls exert a greater pressure on one edge of theslab or strip than the pressure exerted on the other to take care of specific inequalities in the strip existing in the lateral direction such as'inequalities in gauge or temperature.

In the heavy duty reduction of slabs, it has heretofore been found necessary to drive the backing rolls so that they will-in turn frictionally drive the working rolls in the reduction zone of the mill. Attempts to drive the mill by driving the working roll cages while supplying backing through freely rotatable sleeves mounted on driven support shafts have not been found successful because, since possible to the planetary assemblies to reduce the tendency to buckle and to shorten the time interval from furnace to plastic reduction. The pinch rolls may be located in the same housing as the planetary assemblies. This is illustrated in FIG. 1 where like index numerals have been used to indicate like parts. A pair of driven feed rolls 22 and 23 are shown as mounted eccentrically in chocks 24 and 25 which in turn are rotatably mounted in the housing 1. These chocks act in the same way as the chocks 12 and 13 previously described, and may be controlled in the same way as by hydraulic cylinders 26 and 27, the piston rods of which are connected to the chocks.

FIG. 1 shows an embodiment of the invention in which feed rolls, planetary assemblies, and rolls on the exit side of the planetaryassemblies are all mounted in the same housing. The exit rolls may be pinch rolls for tensioning purposes, or they may constitute a two-high planishing mill. Such a mill, in addition to tensioning, tempering,

and ordinary surface functions may serve to iron out any transversely extending ripples or gauge inequalities produced by the operation of the planetary assemblies.

The rolls 40 and 41 which may constitute the planish-.

the drive is applied only to the necks of the working rolls, these rolls may bebrokenor subjected to undue strains, or they must be made larger than is desirable in mills of this type. It is known that a small working roll will produce a greater reduction in the work piece under the same mill pressure.

In FIGS. l, 2 and 6 each backing device consists of a shaft 112 or 113 upon which a backing sleeve 114 or 115 is freely rotatable. As shown most clearly in FIG.

2, the working roll retaining rings 116 and 117 are fixed V on the shaft 112 while the rings 118 and 119 are fixed on the shaft 113. The shafts, therefore, impart a driving force to the rings but not to the sleeves 114 and 115; whichare driven frictionallyby theworking rolls. The difficulties above outlinedare overcome by the provision of means for, urging a number of the working rolls on opposite sides of the roll bite against the backing rolls, such asarcuate shoemembers 120 and 121 on the sides of the planetary assemblies opposite the zone of plastic deformation. These shoes may be lined as at 122 and 123 with a hard substance or a wear resistant material such as plastic to reduce roll wear. The shoes are strongly urged toward the workingroll assemblies 4 and 5. This may be done in various ways. In FIG. 2 each of the shoes is mounted on each end on a bell crank 124 or 125. The intermediate pivotsof these bell cranks are on brackets 126 and 127 mounted on the mill frame. The other ends of the bell cranks are connected to the pistonrods 128 and 129 of a fluid pressurccylinder'lSO containing two pistons in spaced relationship. A similar arrangement, given like index numerals, is shownt'or controlling the lower shoe 121. It will be obvious that the cylinders 130 can be operated to move the shoes underforce against the planetary roll assemblies or to move them in the op positc direction; and it will also be clear that the arrangement may be such as to cause the shoes to follow any scrcwdown movements of the planetary assemblies while continuing to exert the desired degree of pressure on the working rolls.

The result of the operation of the shoes is to. press a number of the working rolls against the backing sleeves 114 and 115 on the side opposite the zone of plastic deformation. The Working rolls are being driven through their respective cages, and irrespective of the presence or absence of a work piece in the mill, the working rolls so pressed by the shoes against the backing sleeves will drive the backng sleeves through friction. 'But because the backing sl ves are so driven, they transmit that drive by friction to such working rolls as may be located in the actual zone of plastic deformation during a rolling operation. Thus, the working rolls which are engaged in the actual reduction of the piece are not being driven solely by the rings at their necks, but are actually being driven frictionally.

The shoes may be configured to press a relatively large number of the working rolls against their respective backing sleeves; and it will be evident also that two or more shoes may be employed with respect to any given planetary assembly. In many instances, in order to compensate for wear, it will be found advisable to mount the choeks for the working rolls in the rings or cages in such fashion that they may be displaced inwardly radially against resilicnt means. Thus the majority of the effective drive on the working rolls which are actually in the zone of plastic deformation will be supplied by friction from the hacking sleeve over the entire line of contact between these working rolls and the backing sleeve.

It may be noted that the shoe arrangement just described reduces the load on the main chocks or bearings of the planetary assembly and tends to prevent deflection of the planetary assembly. By the same token, it also effectively reduces vibration in the mill caused by rapid fluctuations of the roll separating force the passage of each pair of work rolls. This effect is of importance because the actuation of adjusting means as herein described becomes much smoother. There will be found less tendency toward over-correction and consequent shock; and the operation of the adjusting means, especially in producing strip free of back fins on both sides, is made more certain.

In mills where conventional rectangular backing roll chock-s are used, a similar effect so far as the damping of vibrations and the enchancement of the response of the mill to means for adjusting synchronization may be obtained by a method of roll balancing which is shown in FIG. 3. Here a backing roll 131 is shown as having its neck mounted in a chock 132 by means of a main bearing 133. A second bearing 134 is provided as a balancing bearing and is also mounted on the neck of the backing roll and with a separate retaining ring 135. A bolt 136 is connected to the ring and extends upwardly through a portion of the chock, where it is actuated by a spring 137, the force of the spring being greater than the weight of the backing roll 131' and the planetary assembly carried by it.

By such a means, the main bearing 133 may be kept always under load irrespective of the magnitude of the roll eparating forces, which is a function of the angular position of a pair or pairs of working rolls in engagement with the work piece.

FIG. 6 shows an exemplary embodiment of a planetary assembly as shown diagrammatically in FIG. 2, Le. where the work roll carrying cages 116 and 117 are keyed onto the backing shaft 112. Instead of straight keys, said carrying shaft 112 has splined portions 112a and 112b, which engage in corresponding splines provided in the bores of said cages 116 and 117. The shaft 112 is journalled on two cylindrical roller bearings ll2c and 112d, rovided in eccentric chocks 4b and 40. As can be seen,

these bearings allow the shaft 112 an axial freedom; and itsaxial position is controlled by the thrust bearing 141 the inner race of which is firmly attached to the neck of the shaft 112 and moves together with it as one embodiment. The outer races of the bearing 141 are mounted within a collar 158 provided with an external thread. The thread engages with the internal thread of a nut 159 bolted onto the main check 40. A gear 160, keyed on the collar 158, cngagesa pinion 161 which allows for an axial travel of the gear 160.

It will be clear that by turning the pinion 161 either by a hand-operated crank or by any suitable means, the

axial position of the backing shaft 112 can be controlled.

when moving the shaft 112'to the right it will cause a slight rotation of the two roll carrying cages with respect to saidshaft 112. cage 116 turning anti-clockwise and cage 117 clockwise, when observed endwise from the righthand side of the drawing. And vice versa,an adjustment of the axial position of shaft 112 to the left.

produces an opposite rotation of the two cages 116 and 117. This in turn'influences the parallelism of all the working rolls of the corresponding assembly.

It will be noted that such adjustment and control of the axial positions can be made irrespective of whether the mill is stationary or operating.

Referring to FIG. 6, a particular arrangement for mounting the elements of a planetary mill in rotary checks in a housing is detailed. The shaft 112 has necks 138 and 138:: carrying sleeves 139 and 139a. The ring elements 116 and 117 are as above described. The shaft is shown as having a driving coupling 140. The sleeves 139 and 139a are mounted by means of roller bearings 1120 and 112d in the checks 4b and 4c which in turn are rotatably mounted in the housing elements 1a and 1, and retained therein by the retaining ring 163. The sleeve 114 is rotatably mounted on the shaft 112 by anti-friction means 142 or in any other suitable fashion. Various oil sealing elements are indicated in the drawing but need not be specifically outlined here. These permit the delivery of lubricant to the roller bearing 162 and the withdrawal of lubricant therefrom without giving riseto leakage of the lubricant beyond the bearing area where it might cause the working rolls to skid upon sleeve 114.

FIGS. 5 and 6 show the adjustment means for synchronization and parallelism, respectively, when applied to the type of planetary roll mounting where the working roll cages 117 are keyed into a backing shaft 112 (as also shown in FIGS. 1 and 2) and when: the backing rolls 114 are mounted on separate bearings 142 on the same backing shaft. In many cases precision keys or splines are adequate to keep working rolls 5 strictly parallel to each other, but especially in mills producing wide width strips the'operation is greatly facilitated if the operator has at his disposal, quickly responsive and precise means for adjustment of roll parallelism, and even, as above explained,

' throwing the rolls very slightly out of synchronism on purpose.

Adjustments which insure the simultaneous contact of opposite ones of a pair of working rolls with the piece or predetermined departures therefrom are easily attained even while the mill is operating as shown in FIG. 5. Here a pair of backing shaft: 112 and 113, which for convenience are shown close together in the housing 1, are connected by couplings 143 and 144 to spindles 145 and 146 which in turn are connected by couplings 147 and 148 to the shafts 149 and 150 ofa pinion stand 151. Within this pinion stand the shafts are connected together by pinions 152 and 153. A motor or other prime mover may be connected to the projecting end 154 of the shaft 150. In the particular embodiment the pinions have helical teeth and the pinion 153 is made substantially wider than the pinion 152. The last mentioned pinion is splined to the shaft 149 in such a way that it may move longitudinally thereof. A member 155 is threaded into 75 the casing of the pinion stand and has at one end a shoulder which will fix the position of pinion 152, the pinion being urged against the shoulder by spring or other suitable means 156. The member 155 may be adjusted in any suitable fashion as by a wrench. It is shown as having a lock nut 157. However, it is possible to motorize the member 155 in such a way that adjustments in its position can be effected by the operator from a distance. It will be understood that a longitudinal movement of the pinion 152 will vary slightly the relative rotative position of backing shafts 112 and 113 so that working rolls mounted in rings affixed to those shafts can be varied or adjusted as to synchronism.

As has been indicated, prior to this invention whenever a planetary mill began to show signs of operating erratically, the operator had no choice but to endeavor to stop the mill before serious damage occurred. In this application various control features have been described which enable the operator to correct for erratic behavior so as to continue the rolling operation, and a method has been described of operating the mill in such a way as to promptly correct such symptoms before any serious disturbance of the synchronization mechanism and damage has had a chance to occur. It will be evident that the control means herein taught may be modified as to their physical embodiments without departing from the spirit of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as fol lows:

1. In a planetary rolling mill, a housing, a pair of backing shafts journalled eccentrically in chocks rotatively mounted in said housing, means for adjusting the rotative position of said chocks whereby to move said shafts toward and away from each other and equidistantly from the horizontal plane of symmetry, a backing sleeve rotatably mounted on each of said shafts, working rolls having end portions journalled in rings at the ends of said sleeve in a planetary assembly, the rings of each planetary assembly being non-rotatively affixed to the backing shaft of that assembly.

2. The structure claimed in claim 1 wherein means are provided to move said chocks concurrently in the same direction to shift the plane of symmetry of said mill.

3. The structure claimed in claim 1 including means for driving said shafts and means for adjusting the relative rotative positions of said shafts as respects each other whereby to control the simultaneous engagement with a work piece of opposite working rolls of each planetary assembly.

4. The structure claimed in claim 3 wherein said last mentioned means comprises a pinion stand having a pair of shafts interconnected by pinions, said shafts being connected respectively to said backing shafts, said pinions having helical gear teeth, and means for adjusting the position of one of said pinions axially of the pinion stand shaft upon which it is rotated.

5. In a planetary rolling mill, a housing, a pair of backing shafts journalled eccentrically in chocks rotatively mounted in said housing, means for adjusting the rotative position of said chocks whereby to move said shafts toward and away from each other and equidistantly from the horizontal plane of symmetry, a backing sleeve rotatably mounted on each of said shafts, said working rolls journalled in rings at the ends of said sleeves in a planetary assembly, the rings of each planetary assembly being nonrotatively afiixed to the backing shaft of that assembly, and shoe means located on the outer sides of said planetary assemblies, together with power means for actuating said shoe means to cause them to press a plurality of said working rolls against the outer sides of said backing sleeves whereby to drive said backing sleeves, the driving force so imparted to said backing sleeves being transmitted thereto by frictional contact with the working rolls located in an active zone of rolling deformation between the planetary assemblies.

6. In a planetary rolling mill, a housing, a pair of backing shafts journalled with respect to said housing, a backing sleeve rotatably mounted on each of said shafts, working rolls arranged as satellites about said backing sleeves, the end portions of said working rolls being journalled in rings at the ends of said sleeves, the rings of each planetary assembly being non-rotatively affixed to the backing shaft of that assembly, at least one of said rings having a splined connection with its backing shaft, in which connection said splines are helical, and means for adjusting the position of said ring axially of said backing shaft whereby to vary the parallelism of the axes of said working roll to the axis of said backing shaft.

7. The structure claimed in claim 6 wherein said backing shafts have necks with inner and outer portions, chocks located within said housing, one of the portions of each of said necks being provided with a bearing mounted in its chock, the other portion of each of said necks being provided with an indepedent bearing, and means for loading said last mentioned bearing with respect to its chock so as to exert on said shafts forces substantially co-directional with the work roll separating forces of said mill, whereby to render the first mentioned bearings and the entire mill structure less susceptible to vibrations caused by intermittent contacts of said work rolls with a workpiece.

8. The structure claimed in claim 7 in which the said loading is accomplished by providing the second mentioned bearings with rod-like elements extending through portions of said chocks and having loading means with respect to said chocks.

References Cited by the Examiner UNITED STATES PATENTS 285,567 9/83 Carter -56 1,622,744 3/27 Stiefel 801 1.2 2,710,550 6/55 Sendzirnir 8031 WILLIAM J. STEPHENSON, Primary Examiner. 

1. IN A PLANETARY ROLLING MILL, A HOUSING, A PAIR OF BACKING SHAFTS JOURNALLED ECCENTRICALLY IN CHOCKS ROTATIVELY MOUNTED IN SAID HOUSING, MEANS FOR ADJUSTING THE ROTATIVE POSITION OF SAID CHOCKS WHEREBY TO MOVE SAID SHAFTS TOWARD AND AWAY FROM EACH OTHER AND EQUIDISTANTLY FROM THE HORIZONTAL PLANE OF SYMMETRY, A BACKING SLEEVE ROTATABLY MOUNTED ON EACH OF SAID SHAFTS, WORKING ROLLS HAVING END PORTIONS JOURNALLED IN RINGS AT THE ENDS OF SAID SLEEVE IN A PLANETARY ASSEMBLY, THE RINGS OF EACH PLANETARY ASSEMBLY BEING NON-ROTATIVELY AFFICED TO THE BACKING SHAFT OF THAT ASSEMBLY. 